64 ASTEKOIDEA. 



PORCELLANASTERIDtE {see p. 20). 

 CTENODISCIKdE (see p. 20). 



CTENODISCUS. 



Ctenodiscus, M. Tr. Syst. Ast. (1842) p. 76 ; Pen: Arch. Zool. exper. iv. 

 (1875) p. 302; Vig. op. cit. vii. (1878) p. 226. 



With the characters of the subfamily. 



1. Ctenodiscus crispatus. (Plate X. figs. 1-3.) 



Asterias crispata, Retz. Diss. Spec. Ast. (1805) p. 17. 



Asterias polaris, Sabine, Suppl. to Appendix of Parry's Voyage, 

 (1824) p. ccxxiii, pi. i. figs. 2 & 3. 



Astropecten polaris, Gray, Ann. fy May. vi. (1840) p. 180. 



Ctenodiscus polaris, M. Tr. Syst. Ast. (1846) pp. 76 & 129, pi. v. 

 fig. 5. 



Ctenodiscus pvgmasus, id. op. cit. p. 76. 



Ctenodiscus crispatus, Bub. $ Kor. Vet.-Akad. Ildly. 1844 (1846), 

 p. 253; Sars, Nyt Mag. vi. (1851) p. 160; Stimpson, Inv. Grand 

 Manan, (1853) p. 15 ; LiUken, Vid. Medd. 1857, p. 45 ; Sars, Nora. 

 Ech. (1861) p. 26; Verrill, Proc. Post. Soc. N. H. x. (1866) 

 pp. 345 & 356 ; Perrier, Ann. Sci. Nat. xii. (1809) p. 298 ; Stux- 

 berg, (Efv. Vet.-Akad. Fbrh, xxxv. (1879) no. 3, p. 30 ; Jarzynsky, 

 Cat. Ech. in mart albo apud Wagner, Wirbellos. Weiss. Meer. 

 (1885) p. 170. _ 



Ctenodiscus corniculatus, Perrier, Arch. Zool. exper. v. (1875) p. 300 ; 

 Viguier, Arch. Zool. exper. vii. (1878) p. 228; Duncan 8f Sladen, 

 Greenl. Ech. (1881) p. 49 ; Koren fy Danielssen, Norske Nordhavs 

 Ast. (1884) p. 84; Sladen, Chall. Rep. Ast. (1889) p. 171. 



E = 2r. 



General form stellate, with rather deeply incurved sides, flat- 

 tened ; a large terminal plate. Ambulacra wide, with large suckers, 

 and bordered by a row of spines, three to each plate, and externally 

 to them one or two others, which are generally rather smaller. The 

 ventral surface spineless. The marginals with spines ; the supero- 

 marginals are elongated from above downwards and form a vertical 

 wall on every side of the disk ; neither on them nor on the infero- 

 marginals is a spine always developed, but it is generally ; it is 

 never large, and there is never more than one. There are about 

 fifteen marginals on either side of each arm. The paxilliform 

 plates of the upper surface are very delicately stellate and closely 

 packed. The madreporite, which is distinct and rather deeply 

 grooved, is not far from the margin of the disk. 



Colour in spirit creamy yellow. 



E. r. 



28-5 14 



26 14 



24 11 



